Stir fry the masala ingredients in the oil until they are light gold and fragrant. Transfer to a blender and grind with just enough water to make a smooth paste.
In a saucepan, heat the remaining oil.
Add the mustard and cumin seeds and when they sputter, add the curry leaves
Add ½ cup of water and tamarind paste.
Bring to a boil, then add tomatoes.
When the tomatoes break down slightly, add the ground masala paste.
Bring to a boil and simmer for about 5 minutes.
Add the dal and "stock" and salt to taste.
Bring to a rolling boil and let it boil about 5 minutes.
Garnish with coriander and serve hot.